Temperatures in September
It's warm in September in Portsmouth with an average temperature of 23°C. Temperatures this month range from a low of 18°C to a high of 28°C. At night, you can expect temperatures between 9°C and 18°C.
Max and Min Temperatures per Day
This chart shows the daily maximum and minimum temperatures in degrees Celsius for Portsmouth in September. The red line indicates the max temperatures, and the blue line shows the minimums.
Start of September
The month of September starts in Portsmouth with warm temperatures, averaging around 26°C during the day and nights close to 16°C. You can expect regular precipitation, but there’s also a chance for some sunny days in the first days of the month.
Since temperatures can differ between day and night, it’s a good idea to dress in layers.
Mid-September
By mid-September, the average daytime temperature drops to around 24°C, with nights close to 15°C. During this part of the month, you can expect regular precipitation, but there’ll also be some sunny days.
End of September
By the end of September, the average daytime temperature in Portsmouth will be around 22°C, with nights close to 12°C. There’s regular precipitation, but with a bit of luck, you’ll also get some dry and sunny days.
Discover cheap trips to Portsmouth 
Precipitation in September
In September, there is an average of 163 mm of precipitation, spread over 7 days. The wind speed is around 4 Bft, mostly coming from the South.
The average precipitation chance is 22% per day this month. Though that seems low, there are also a few days with a higher chance of precipitation.
Precipitation Chance
This chart shows the daily precipitation chance (in percentages) in September for Portsmouth. 0% means it never rained on that day in the past 10 years, and 100% means it rained every day. All values in between represent the average chance of precipitation on that day.
Portsmouth in September |
London | ||
|---|---|---|---|
 Average Temperature |
23°C | 20°C | |
 High Temp |
28°C | 22°C | |
| Low Temp |
18°C | 17°C | |
 Total Precipitation |
163 mm | 44 mm | |
| Rainy Days |
7 days | 8 days | |
August
UV index
The UV index is a maximum of 7 this month. That's a moderate to high value on the intensity scale of 1 to 11. Unprotected skin can burn within 15-25 minutes.
Is September a good time to visit Portsmouth?
After some sun? Then September isn’t the best time to be in Portsmouth. The temperature is pleasant, but there’s too much chance of rain this month.
Temperature records for Portsmouth in September
With 35°C, Portsmouth hit the highest temperature in the last 10 years in September 2015. The lowest daytime temperature in this month was 11°C in 2017. The extreme night temperatures ranged from a low of 2°C to a high of 22°C.
Check out the climate of Portsmouth for all months and discover the best travel time
Plan your next holiday
Don’t miss the best holiday deals for Portsmouth and see what our partners have for you.
Daily Temperature in September in Portsmouth
This chart shows the average daily temperatures, both day and night, for each day in September in Portsmouth, measured in degrees Celsius. The red line represents the maximum temperatures, while the blue line shows the minimums. The days of the month are displayed at the bottom of the chart. The data, based on historical observations, gives an overview of the average daily temperatures during this month.
Daily Precipitation in September in Portsmouth
The chart below shows the average daily precipitation in September for Portsmouth, measured in millimetres over the past years. Precipitation is always measured as water, even if it’s snow or hail. The days of the month are shown at the bottom of the chart.
A low average precipitation means that the chance of rain on that day is usually small, while a higher average suggests that rain is more likely. But it’s still an average, so each day can be different. Based on historical weather data for September, you can expect around 7 days of rain in Portsmouth.
Daily UV Index in September in Portsmouth
This chart shows the average daily UV index in September in Portsmouth, with the UV index ranging from 0 to a maximum of 11. The bottom of the chart shows the days of the month. Based on historical data, this chart provides an idea of the daily UV radiation levels you can expect.
Temperature in September in Portsmouth Over the Years
This chart shows the average temperature in September in Portsmouth, measured in degrees Celsius, over the past years.
Total Precipitation in September in Portsmouth Over the Years
This chart shows the average precipitation in September in Portsmouth, measured in millimetres over the past years. Precipitation is always measured as water, even if it’s snow or hail.
Daily climate in September for Portsmouth
Click on a specific day in September for detailed info on the typical weather on that day in Portsmouth. Check out the historical temperatures and precipitation over the past 10 years on this day.
Weather experiences in September in Portsmouth
Have you been to Portsmouth in September?
Share your weather experience in September in Portsmouth.
Average Weather in Portsmouth by Month
Click on a month below to see detailed weather info for Portsmouth. Based on historical weather data, you can see the average temperature, precipitation, wind, and UV index for each day of the month.
Or check out the climate of Portsmouth for all months at once
